Conventional size formulation systems associated with slashers in textile processing plants have a number of drawbacks associated therewith. In typical systems a size formulation mixer and two storage tanks are required to supply the size box associated with each slasher. Whenever a run through a slasher with a given size formulation was completed, the size formulation remaining in the size boxes was sewered, and there was substantial down time of the slasher while a new batch was laboriously mixed. Precise control of the size formulation was also difficult, wide temperature variations at the point of size formula application resulted due to variations in the amounts of diluent used, etc., and in general there was a great deal of waste of energy, labor, and material.
According to the present invention a method and apparatus are provided which overcome the drawbacks associated with prior art size formulation and supply techniques and systems. According to the present invention size formulation and supply can be practiced with predictability and repeatability with minimum slasher down time, minimum labor input, and minimum waste of energy and material. Additionally the apparatus according to the invention substantially reduces the floor space required for the size formulation and supply functions, with attendant advantages. The composition and temperature of the size formulation is precisely and reliably controllable, and all formulation and supply functions can be readily controlled by a single computer control means.
According to the present invention the mixing and heating of a number of size formulation components to produce a size formulation having a predetermined composition and temperature is greatly simplified. A single mixing tank can supply the size formulation for all the size boxes associated with a plurality of slashers. A granular size component, such as PVA, is supplied through a closed pneumatic loop to a weigh hopper, which periodically discharges the size component into the mixing tank. Other size components such as water, defoamer, and wax are also added to the tank, and heating is accomplished by pumping the formulation from the tank through an interfacial surface generation (ISG) heat exchanger, and then back to the tank. After mixing and heating, the size formulation is dumped into a holding tank, the holding tank being disposed in a closed loop which continuously circulates the size formulation past each of the size boxes.
A plurality of formula stations are provided adjacent the size boxes. At least one formula station is operatively associated with each size box. At the formula stations, further additional size formulation components are added to the size formulation and mixed therewith to provide a homogeneous altered size formulation prior to passage of the size formulation into a size box. Tints, density control fluids, reclaimed size, diluent, and other components may be added at the formula stations, and mixing is accomplished using an ISG mixer. Valve and pump means within the formula station are activated by a radio transmitter level control associated with each size box so that the appropriate level of size formulation is always provided in each size box.
As the size formulation circulates in the closed loop, the temperature thereof is reduced from the mixing temperature (typically about 195.degree. F.) to the use temperature (typically about 150.degree.-160.degree. F.). This is accomplished by passing it through a recovery heat exchanger in heat-exchanging relationship with diluent (e.g. water) that is also circulated through the heat exchanger. The diluent is then supplied to the formula station to be mixed with the size formulation where desired.
When the size formulation in the size box is to be replaced, it is drained from the size box and circulated into a reclamation system rather than being sewered. In the reclamation system it can be filtered and/or passed through ion exchange media, and/or through sorption media, and the solids content thereof can be analyzed. After all undesirable components are removed therefrom it can be ultimately returned to the size boxes for reuse. This can be done either by passing it to the virgin size mixing tank, or circulating it in a closed loop past and to the formula stations.
It is the primary object of the present invention to provide a method and system for efficiently and effectively supplying size to size boxes associated with slashers. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.